A so-called general-purpose engine used for agricultural working machines and the like often includes a so-called recoil starter which performs cranking by pulling a rope. Since this recoil starter needs to vigorously and greatly pull the rope, there are cases in which a starting manipulation of an engine becomes a burden on elderly users or the like.
In automobiles and the like, a self-starter is mounted for starting the engine. When the self-starter is used in this way, the engine can be easily started with only a switch manipulation. As a power supply of the self-starter, in many cases, a lead storage battery is used in terms of maintenance and capacity. The lead storage battery used to start the engine is generally large and heavy. Although there is no problem when an installation space is sufficient as in a vehicle such as an automobile, there are cases in which it is difficult to install the lead storage battery in terms of weight increase or securing of the installation space when trying to install the lead storage battery in an agricultural working machine or the like.
Patent Document 1 suggests a technique for reducing a burden on a user caused at the time of starting an engine of a working machine or the like. In Patent Document 1, a self-starter that performs cranking using the power of an electric motor is added to a small engine, and a battery pack made of a lithium secondary battery is housed in a switch box provided at a different position from the small engine.